Quality Assurance Testing for Modern Optical Imaging Systems

TLDR

Instrument performance can no longer be assessed visually; users and agencies require confidence that data from optical imaging systems is uniform and quantifiable over time and across instruments, ideally with stable lasers, uniform illumination, and perfect color alignment. The study aimed to evaluate current microscope performance through three image‑based tests and to develop cross‑platform standards that enhance quantitative measurement validity. The study employed three image‑based tests—long‑ and short‑term illumination stability, multi‑wavelength signal co‑registration, and field illumination uniformity—using quantitative thresholds of 10%/3% power deviation, >1 pixel bead center‑of‑mass shift, and 10%/20% field deviation. The tests revealed the current performance state of microscopes and defined relative standards that help cores maintain optimal conditions, thereby improving quantitative measurement validity.

Abstract

Abstract The days of being able to ascertain instrument performance by simply peering through the eye pieces at a specimen are gone. However, users and granting agencies need to be confident that data collected on these instruments is uniform and quantifiable both over time and between instruments. Ideally, a LASER should not fluctuate, illumination should be completely uniform, and colors should be perfectly aligned. To check the current performance of imaging equipment, we conducted a worldwide research study utilizing three image-based tests: long-/short-term illumination stability, co-registration of signals across various wavelengths, and field illumination uniformity. To differentiate between “acceptable” and “unacceptable” performance, the deviation in illumination power could not exceed 10% (long term) or 3% (short term), the difference in the center-of-mass of imaged multicolored beads could not exceed >1 pixel between different wavelengths, and field illumination values could not exceed 10% (horizontal) or 20% (diagonal) deviation. This study established the current state of microscope performance through simple, efficient, and robust tests, while defining relative standards to assist cores in maintaining their instruments in optimal operating conditions. We developed cross-platform performance standards that will improve the validity of quantitative measurements made using various light microscopes.